A 13-year-old boy was shot and critically wounded Monday outside a school, authorities said. Police in neighboring Montgomery County hunting for a serial sniper rushed investigators to the scene, and anxious parents streamed in to retrieve their children. On Wednesday and Thursday, five people were shot to death by a sniper in a 16-hour span in Montgomery County. A sixth victim was killed Thursday in Washington, D.C. On Friday, a woman was shot and wounded in Virginia. So what sort of person is likely to carry out these shootings? Who should the police be looking for? Ask former FBI profiler Gregg McCrary.

Gregg McCrary is currently with Behavioral Criminology International. He is also a crime consultant for the Today Show and NBC Nightly News.

Washington, D.C.:
Based on the evidence so far, what sort of a perpetrator (or perpetrators) would you recommend the police look for?

Gregg McCrary:
The physical forensic evidence is limited to the bullets that have been recovered, and the behavioral evidence and geography points to someone probably anchored to or familiar with the Montgomery County area, who is emotionally distraught. Someone who has had experience with a .223 caliber weapon. The information that will probably lead to his identification will probably come from the public, who will know someone like this and call information into the authorities.erie, pa:
Your work is both horrific and interesting at once. Have you found similarities in these killers childhoods? Also, have you ever done a workup on their chemistry to see if there are abnormailties that relate?

Gregg McCrary:
What we know about the development of serial or spree killers is that it's a not well understood combination of nature and nurture. There are some environmental factors that have played a role in the development of some killers, yet not in others.Mesa, Arizona:
Today's victim was in his teens. The others were in their 20's, 30's, 40's, 50's, and 60's (possibly looked in 60's). Is there any correlation? Would the next victims possibly be a 70 year old or a young child?

Gregg McCrary:
I don't know that we know that the school shooting today is definitely related, but if it is, then I think this would be evidence of this killer's primary motive, which is to outrage and shock the community. The victims all appear quite random, but by shooting a child this will outrage the community even moreso and make everyone feel more vulnerable, which is the goal of this particular killer.Washington, D.C.:
The media were reporting there is "geographical profiling" being applied in the investigation of these shootings. What does that mean?

Gregg McCrary:
It is a specific type of profiling, where the geographical coordinates of every incident are put into a computer program, and along with an actual physical visit to each scene, an area of interest is developed. this will be used to prioritize leads; in other words, if someone calls in and talks about someone emotionally distraught with access to a weapon like this and they're from the area highlighted by the profile, that lead will be prioritized. Geographical and behavioral profiling allow investigators to prioritize the hundreds of leads coming in.dayton, oh:
i am currently doing a research project on profilers and was wondering what kind of schooling you need to become a profiler?

Gregg McCrary:
The FBI chooses its profilers from its seasoned agents. It takes some academic background in psychology, but more importantly it takes a lot of investigative experience, because the purpose of a profile is to aid in the investigation of a crime.Fredericksburg, VA:
With the different races, sexes and ages, could the shooter be a trophy killer shooting one of each? Also with the quiet weekend could the killer be doing this on his job?

Gregg McCrary:
Those are both possibilities. Again, this assumes that the shooting today is related. It's interesting he was quiet on the weekend, since most of us are tied up during the week and free to do what we like on the weekend.Scotland:
Do you believe that the shooter is fullfilling some kind of fantasy or possibliy reacking some kind of revenge??

Gregg McCrary:
Probably some of each. He has fantasized and thought about this crime before doing it, and he could be striking out against a society he feels has wronged him in some way.Alexandria, Virginia:
How accurate is profiling?

Gregg McCrary:
It depends on how you measure it. There's no simple answer to this question, but with that said the studies the FBI has conducted internally, we feel we're 70-80% accurate on the profiles we've constructed.Linden, VA:
Why would the shooter, after committing his crimes in Maryland, travel to Fredericksburg, Virginia? Is it in order to get the FBI involved?

Gregg McCrary:
I think it's probably just a matter of displacement, that the intense police investigation and increased vigilance of the community in Maryland probably forced him out, and he went to Fredericksburg because the community wasn't on such a high state of alert. That allowed him to commit his crime and disappear without as much risk as in Maryland.White Plains, NY:
In shootings where there is no bullet to match bullets recovered in previous shootings--and the type of rifle and the scenario is identical--is there a way to tell if the gunman is most likely the same gunman or is a copycat.

Gregg McCrary:
There would be no way to positively identify it as the same weapon unless there is a bullet to compare it to. I don't believe that any shell casings have been recovered, so we don't have any of those to compare.Washington, D.C.:
What's the technical difference between a serial killer and a thrill killer?

Gregg McCrary:
A spree or thrill killer typically has a very short cooling off period between homicides, where a serial killer may have days, weeks and months between homicides. In this case, we have a killer whose initial spree was done very quickly. Now he may have taken as much as a weekend off if he's responsible for the school shooting.Augusta, Maine:
Some people, particularly among the right-wing talk shows, are suggesting Islamic extremism at work in this matter. Do you see any real hint of that?

Gregg McCrary:
No I don't at this point. This is terrorism in the broad sense, in that it's isolated acts of violence instilling fear in the community, but at this point there is no reason or evidence to connect it to any religious or political extremist group.